Bread has traditionally been made in batch processes. The major processes used in New Zealand are the Bulk Fermentation Process and the Mechanical Dough Development Process. In the bulk fermentation process all the dough ingredients are mixed into a homogeneous mass, without doing an unnecessary amount of work. The dough is set aside for a set period of bulk fermentation. The fermentation time can vary widely but is now commonly two hours. A typical formula is as follows:
______________________________________ Flour 100 Kg Water 59-63 kg Yeast 3 kg Salt 2 kg Sugar 2 kg Fat 2 kg Potassium bromate 30 ppm. ______________________________________
As fermentation takes place the dough changes slowly from a dense mass lacking extensibility and with poor gas retention properties, into a smooth extensible dough with good gas retention properties. After fermentation the dough is divided into loaf-sized pieces, given an intermediate "proof" of about ten minutes, and then shaped (moulded).
The moulding process is vital in producing the correct bubble structure in the dough. If a fine uniform cell structure is desired in the bread, final moulding will be required to expel gas and cause large bubbles to collapse to create many smaller bubbles. The dough is then given a final proof of fifty minutes to expand almost to its full size then baked.
During the long fermentation of the fermentation group of processes there is an appreciable loss of flour solids due to their conversion to volatile substances. This loss is economically disadvantageous. In the search for ways of eliminating the need for long periods of fermentation, and also of reducing the loss of flour solids, mechanical dough development was discovered. By this technique, desirable changes in the physical properites of the dough, normally brought about by fermentation, are achieved by a short period of intense mechanical development in the presence of added fat and a moderately high level of a synthetic oxidising agent.
In mechnical dough development the initial fermentation step is replaced by a short period of intense mixing in a special high powered batch mixer that imparts between 5 and 12 Wh/kg (Watt-hours per kilogram) of work to all the dough ingredients in two to four minutes. Such mixers are usually operated under a partial vacuum to improve the crumb texture. The dough is then treated as for a bulk fermentation dough, that is, it is divided, given 10 minutes intermediate proof, moulded, given 50 minutes final proof and baked.
While this mechanical dough development process succeeds in reducing fermentation time and loss of flour solids, there are still inherent difficulties. The addition of a synthetic oxidising agent (potassium bromate) is undesirable for some markers.
The dough from the end of a batch waits longer to be processed than the dough from the start of a batch, leading to changes in dough consistency within batches. The intermediate proof step is still needed. A high-powered motor is required, which is used only intermittently. Further, the process is still a batch process, which is inconvenient for automation.
The object of the present invention is to provide a dough development process and apparatus which will go at least some way towards avoiding the above disadvantages.